/*
 * WPA Supplicant / shared MSCHAPV2 helper functions / RFC 2433 / RFC 2759
 * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "sha1.h"
#include "ms_funcs.h"
#include "crypto.h"


/**
 * challenge_hash - ChallengeHash() - RFC 2759, Sect. 8.2
 * @peer_challenge: 16-octet PeerChallenge (IN)
 * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
 * @username: 0-to-256-char UserName (IN)
 * @username_len: Length of username
 * @challenge: 8-octet Challenge (OUT)
 * Returns: 0 on success, -1 on failure
 */
static int challenge_hash(const u8 *peer_challenge, const u8 *auth_challenge,
        const u8 *username, size_t username_len,
        u8 *challenge)
{
    u8 hash[SHA1_MAC_LEN];
    const unsigned char *addr[3];
    size_t len[3];

    addr[0] = peer_challenge;
    len[0] = 16;
    addr[1] = auth_challenge;
    len[1] = 16;
    addr[2] = username;
    len[2] = username_len;

    if (sha1_vector(3, addr, len, hash))
        return -1;
    os_memcpy(challenge, hash, 8);
    return 0;
}


/**
 * nt_password_hash - NtPasswordHash() - RFC 2759, Sect. 8.3
 * @password: 0-to-256-unicode-char Password (IN; ASCII)
 * @password_len: Length of password
 * @password_hash: 16-octet PasswordHash (OUT)
 * Returns: 0 on success, -1 on failure
 */
int nt_password_hash(const u8 *password, size_t password_len,
        u8 *password_hash)
{
    u8 buf[512], *pos;
    size_t i, len;

    if (password_len > 256)
        password_len = 256;

    /* Convert password into unicode */
    for (i = 0; i < password_len; i++) {
        buf[2 * i] = password[i];
        buf[2 * i + 1] = 0;
    }

    len = password_len * 2;
    pos = buf;
    return md4_vector(1, (const u8 **) &pos, &len, password_hash);
}


/**
 * hash_nt_password_hash - HashNtPasswordHash() - RFC 2759, Sect. 8.4
 * @password_hash: 16-octet PasswordHash (IN)
 * @password_hash_hash: 16-octet PasswordHashHash (OUT)
 * Returns: 0 on success, -1 on failure
 */
int hash_nt_password_hash(const u8 *password_hash, u8 *password_hash_hash)
{
    size_t len = 16;
    return md4_vector(1, &password_hash, &len, password_hash_hash);
}


/**
 * challenge_response - ChallengeResponse() - RFC 2759, Sect. 8.5
 * @challenge: 8-octet Challenge (IN)
 * @password_hash: 16-octet PasswordHash (IN)
 * @response: 24-octet Response (OUT)
 */
void challenge_response(const u8 *challenge, const u8 *password_hash,
        u8 *response)
{
    u8 zpwd[7];
    des_encrypt(challenge, password_hash, response);
    des_encrypt(challenge, password_hash + 7, response + 8);
    zpwd[0] = password_hash[14];
    zpwd[1] = password_hash[15];
    os_memset(zpwd + 2, 0, 5);
    des_encrypt(challenge, zpwd, response + 16);
}


/**
 * generate_nt_response - GenerateNTResponse() - RFC 2759, Sect. 8.1
 * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
 * @peer_challenge: 16-octet PeerChallenge (IN)
 * @username: 0-to-256-char UserName (IN)
 * @username_len: Length of username
 * @password: 0-to-256-unicode-char Password (IN; ASCII)
 * @password_len: Length of password
 * @response: 24-octet Response (OUT)
 * Returns: 0 on success, -1 on failure
 */
int generate_nt_response(const u8 *auth_challenge, const u8 *peer_challenge,
        const u8 *username, size_t username_len,
        const u8 *password, size_t password_len,
        u8 *response)
{
    u8 challenge[8];
    u8 password_hash[16];

    challenge_hash(peer_challenge, auth_challenge, username, username_len,
            challenge);
    if (nt_password_hash(password, password_len, password_hash))
        return -1;
    challenge_response(challenge, password_hash, response);
    return 0;
}


/**
 * generate_nt_response_pwhash - GenerateNTResponse() - RFC 2759, Sect. 8.1
 * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
 * @peer_challenge: 16-octet PeerChallenge (IN)
 * @username: 0-to-256-char UserName (IN)
 * @username_len: Length of username
 * @password_hash: 16-octet PasswordHash (IN)
 * @response: 24-octet Response (OUT)
 * Returns: 0 on success, -1 on failure
 */
int generate_nt_response_pwhash(const u8 *auth_challenge,
        const u8 *peer_challenge,
        const u8 *username, size_t username_len,
        const u8 *password_hash,
        u8 *response)
{
    u8 challenge[8];

    if (challenge_hash(peer_challenge, auth_challenge,
                username, username_len,
                challenge))
        return -1;
    challenge_response(challenge, password_hash, response);
    return 0;
}


/**
 * generate_authenticator_response_pwhash - GenerateAuthenticatorResponse() - RFC 2759, Sect. 8.7
 * @password_hash: 16-octet PasswordHash (IN)
 * @nt_response: 24-octet NT-Response (IN)
 * @peer_challenge: 16-octet PeerChallenge (IN)
 * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
 * @username: 0-to-256-char UserName (IN)
 * @username_len: Length of username
 * @response: 20-octet AuthenticatorResponse (OUT) (note: this value is usually
 * encoded as a 42-octet ASCII string (S=hexdump_of_response)
 * Returns: 0 on success, -1 on failure
 */
int generate_authenticator_response_pwhash(
        const u8 *password_hash,
        const u8 *peer_challenge, const u8 *auth_challenge,
        const u8 *username, size_t username_len,
        const u8 *nt_response, u8 *response)
{
    static const u8 magic1[39] = {
        0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
        0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
        0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
        0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74
    };
    static const u8 magic2[41] = {
        0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
        0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
        0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
        0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
        0x6E
    };

    u8 password_hash_hash[16], challenge[8];
    const unsigned char *addr1[3];
    const size_t len1[3] = { 16, 24, sizeof(magic1) };
    const unsigned char *addr2[3];
    const size_t len2[3] = { SHA1_MAC_LEN, 8, sizeof(magic2) };

    addr1[0] = password_hash_hash;
    addr1[1] = nt_response;
    addr1[2] = magic1;

    addr2[0] = response;
    addr2[1] = challenge;
    addr2[2] = magic2;

    if (hash_nt_password_hash(password_hash, password_hash_hash))
        return -1;
    if (sha1_vector(3, addr1, len1, response))
        return -1;

    challenge_hash(peer_challenge, auth_challenge, username, username_len,
            challenge);
    return sha1_vector(3, addr2, len2, response);
}


/**
 * generate_authenticator_response - GenerateAuthenticatorResponse() - RFC 2759, Sect. 8.7
 * @password: 0-to-256-unicode-char Password (IN; ASCII)
 * @password_len: Length of password
 * @nt_response: 24-octet NT-Response (IN)
 * @peer_challenge: 16-octet PeerChallenge (IN)
 * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
 * @username: 0-to-256-char UserName (IN)
 * @username_len: Length of username
 * @response: 20-octet AuthenticatorResponse (OUT) (note: this value is usually
 * encoded as a 42-octet ASCII string (S=hexdump_of_response)
 * Returns: 0 on success, -1 on failure
 */
int generate_authenticator_response(const u8 *password, size_t password_len,
        const u8 *peer_challenge,
        const u8 *auth_challenge,
        const u8 *username, size_t username_len,
        const u8 *nt_response, u8 *response)
{
    u8 password_hash[16];
    if (nt_password_hash(password, password_len, password_hash))
        return -1;
    return generate_authenticator_response_pwhash(
            password_hash, peer_challenge, auth_challenge,
            username, username_len, nt_response, response);
}


/**
 * nt_challenge_response - NtChallengeResponse() - RFC 2433, Sect. A.5
 * @challenge: 8-octet Challenge (IN)
 * @password: 0-to-256-unicode-char Password (IN; ASCII)
 * @password_len: Length of password
 * @response: 24-octet Response (OUT)
 * Returns: 0 on success, -1 on failure
 */
int nt_challenge_response(const u8 *challenge, const u8 *password,
        size_t password_len, u8 *response)
{
    u8 password_hash[16];
    if (nt_password_hash(password, password_len, password_hash))
        return -1;
    challenge_response(challenge, password_hash, response);
    return 0;
}


/**
 * get_master_key - GetMasterKey() - RFC 3079, Sect. 3.4
 * @password_hash_hash: 16-octet PasswordHashHash (IN)
 * @nt_response: 24-octet NTResponse (IN)
 * @master_key: 16-octet MasterKey (OUT)
 * Returns: 0 on success, -1 on failure
 */
int get_master_key(const u8 *password_hash_hash, const u8 *nt_response,
        u8 *master_key)
{
    static const u8 magic1[27] = {
        0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
        0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
        0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79
    };
    const unsigned char *addr[3];
    const size_t len[3] = { 16, 24, sizeof(magic1) };
    u8 hash[SHA1_MAC_LEN];

    addr[0] = password_hash_hash;
    addr[1] = nt_response;
    addr[2] = magic1;

    if (sha1_vector(3, addr, len, hash))
        return -1;
    os_memcpy(master_key, hash, 16);
    return 0;
}


/**
 * get_asymetric_start_key - GetAsymetricStartKey() - RFC 3079, Sect. 3.4
 * @master_key: 16-octet MasterKey (IN)
 * @session_key: 8-to-16 octet SessionKey (OUT)
 * @session_key_len: SessionKeyLength (Length of session_key) (IN)
 * @is_send: IsSend (IN, BOOLEAN)
 * @is_server: IsServer (IN, BOOLEAN)
 * Returns: 0 on success, -1 on failure
 */
int get_asymetric_start_key(const u8 *master_key, u8 *session_key,
        size_t session_key_len, int is_send,
        int is_server)
{
    static const u8 magic2[84] = {
        0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
        0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
        0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
        0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
        0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
        0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
        0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
        0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
        0x6b, 0x65, 0x79, 0x2e
    };
    static const u8 magic3[84] = {
        0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
        0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
        0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
        0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
        0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
        0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
        0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
        0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
        0x6b, 0x65, 0x79, 0x2e
    };
    static const u8 shs_pad1[40] = {
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
    };

    static const u8 shs_pad2[40] = {
        0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
        0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
        0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
        0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
    };
    u8 digest[SHA1_MAC_LEN];
    const unsigned char *addr[4];
    const size_t len[4] = { 16, 40, 84, 40 };

    addr[0] = master_key;
    addr[1] = shs_pad1;
    if (is_send) {
        addr[2] = is_server ? magic3 : magic2;
    } else {
        addr[2] = is_server ? magic2 : magic3;
    }
    addr[3] = shs_pad2;

    if (sha1_vector(4, addr, len, digest))
        return -1;

    if (session_key_len > SHA1_MAC_LEN)
        session_key_len = SHA1_MAC_LEN;
    os_memcpy(session_key, digest, session_key_len);
    return 0;
}


#define PWBLOCK_LEN 516

/**
 * encrypt_pw_block_with_password_hash - EncryptPwBlockWithPasswordHash() - RFC 2759, Sect. 8.10
 * @password: 0-to-256-unicode-char Password (IN; ASCII)
 * @password_len: Length of password
 * @password_hash: 16-octet PasswordHash (IN)
 * @pw_block: 516-byte PwBlock (OUT)
 * Returns: 0 on success, -1 on failure
 */
int encrypt_pw_block_with_password_hash(
        const u8 *password, size_t password_len,
        const u8 *password_hash, u8 *pw_block)
{
    size_t i, offset;
    u8 *pos;

    if (password_len > 256)
        return -1;

    os_memset(pw_block, 0, PWBLOCK_LEN);
    offset = (256 - password_len) * 2;
    if (os_get_random(pw_block, offset) < 0)
        return -1;
    for (i = 0; i < password_len; i++)
        pw_block[offset + i * 2] = password[i];
    /*
     * PasswordLength is 4 octets, but since the maximum password length is
     * 256, only first two (in little endian byte order) can be non-zero.
     */
    pos = &pw_block[2 * 256];
    WPA_PUT_LE16(pos, password_len * 2);
    rc4_skip(password_hash, 16, 0, pw_block, PWBLOCK_LEN);
    return 0;
}


/**
 * new_password_encrypted_with_old_nt_password_hash - NewPasswordEncryptedWithOldNtPasswordHash() - RFC 2759, Sect. 8.9
 * @new_password: 0-to-256-unicode-char NewPassword (IN; ASCII)
 * @new_password_len: Length of new_password
 * @old_password: 0-to-256-unicode-char OldPassword (IN; ASCII)
 * @old_password_len: Length of old_password
 * @encrypted_pw_block: 516-octet EncryptedPwBlock (OUT)
 * Returns: 0 on success, -1 on failure
 */
int new_password_encrypted_with_old_nt_password_hash(
        const u8 *new_password, size_t new_password_len,
        const u8 *old_password, size_t old_password_len,
        u8 *encrypted_pw_block)
{
    u8 password_hash[16];

    if (nt_password_hash(old_password, old_password_len, password_hash))
        return -1;
    if (encrypt_pw_block_with_password_hash(new_password, new_password_len,
                password_hash,
                encrypted_pw_block))
        return -1;
    return 0;
}


/**
 * nt_password_hash_encrypted_with_block - NtPasswordHashEncryptedWithBlock() - RFC 2759, Sect 8.13
 * @password_hash: 16-octer PasswordHash (IN)
 * @block: 16-octet Block (IN)
 * @cypher: 16-octer Cypher (OUT)
 */
void nt_password_hash_encrypted_with_block(const u8 *password_hash,
        const u8 *block, u8 *cypher)
{
    des_encrypt(password_hash, block, cypher);
    des_encrypt(password_hash + 8, block + 7, cypher + 8);
}


/**
 * old_nt_password_hash_encrypted_with_new_nt_password_hash - OldNtPasswordHashEncryptedWithNewNtPasswordHash() - RFC 2759, Sect. 8.12
 * @new_password: 0-to-256-unicode-char NewPassword (IN; ASCII)
 * @new_password_len: Length of new_password
 * @old_password: 0-to-256-unicode-char OldPassword (IN; ASCII)
 * @old_password_len: Length of old_password
 * @encrypted_password_hash: 16-octet EncryptedPasswordHash (OUT)
 * Returns: 0 on success, -1 on failure
 */
int old_nt_password_hash_encrypted_with_new_nt_password_hash(
        const u8 *new_password, size_t new_password_len,
        const u8 *old_password, size_t old_password_len,
        u8 *encrypted_password_hash)
{
    u8 old_password_hash[16], new_password_hash[16];

    if (nt_password_hash(old_password, old_password_len,
                old_password_hash) ||
            nt_password_hash(new_password, new_password_len,
                new_password_hash))
        return -1;
    nt_password_hash_encrypted_with_block(old_password_hash,
            new_password_hash,
            encrypted_password_hash);
    return 0;
}
